He came in a distant fourthin the Iowa caucus, and polls show that he’ll do no better in New Hampshire on Tuesday. But as he tours this state boasting about accomplishments real and imagined, it’s a wonder all his chest-thumping hasn’t bruised his ribs.

“In 1980, I helped design a key part of the Reagan campaign,” announced Gingrich, who was a freshman legislator at the time.

“I worked with Reagan in the early ’80s,” he went on, “developing a strategy for the Soviet empire.”

Ah, so it was Gingrich, a backbencher in the minority party in the House, who vanquished the Red Menace!

“In the late ’70s, working with Jack Kemp, Art Laffer, Jude Wanniski. . . we developed supply-side economics.”

That Laffer Curve? It’s really the Gingrich Curve.

“I’ve written several novels on the American Revolutionary War,” he adds.

“I did two movies.”

“I helped create the Hart-Rudman Commission.”

The self-adulation envelops him: “largest capital-gains tax cut in history . . . only time in your lifetime . . . as good a campaign by a legislative body that was run in American history . . . largest one-party increase in an off-year election in American history.”

Me! Largest! First! Best! Gingrich talks often on the stump about “American exceptionalism,” but his campaign seems to be based on the theory of Newtonian exceptionalism.

Some say that he continues his long-shot campaign because he’s driven by his loathing of Mitt Romney — but his attacks on the front-runner have been inconsistent. Some say that he’s trying to provide a conservative alternative — but his candidacy, by splitting the conservative vote, is doing the opposite.

A better explanation is that his campaign bus is on an ego trip. No question, the man earned a place in history by leading Republicans to power in the House. But the endless boasts suggest delusions of grandeur. “You want to have somebody who actually changed Washington,” he tells supporters, “and I worked with both Reagan and Thatcher on that scale of change.”

Then he went on to create the Internet.

The Gingrich pitch in New Hampshire includes his usual collection of wild allegations against President Obama and the Democrats: “Radicalism . . . imperial presidency . . . trying to buy reelection by cutting deals in violation of the law . . . European socialist . . . dictatorial.” He also delights in tearing down the man likeliest to be his party’s nominee: “A Massachusetts moderate . . . tax-paid abortions . . . raised taxes . . . appointed liberal judges.”

Evidently, the people of Plymouth, N.H., didn’t realize how lucky they were to hear Gingrich for free, because there were empty seats in the old train depot when he presented his auto-hagiography last week.

“Unemployment while I was speaker dropped to 4.2 percent,” he said, neglecting to share credit with Bill Clinton.

A woman asked about Social Security. “I was strategic adviser to the president of AARP,” Gingrich informed her.

A man asked Gingrich to compare himself with Rick Santorum. Gingrich explained that the difference was his “real experience in working with Reagan and Margaret Thatcher.”

“Welfare reform wouldn’t have happened if I hadn’t been speaker,” he elaborated. “All of the negotiating at the level of getting [Clinton] to sign it was at my level.”

A few more boasts, and Gingrich was ready to move on to a question about the United Nations, which allowed him to brag that “I co-chaired with Senate Majority Leader George Mitchell a United Nations reform task force.”

An hour later, Gingrich was in Littleton, in New Hampshire’s White Mountains, and his opinion of himself had only climbed. “We became the first reelected House Republican majority since 1928,” he informed them.

A questioner asked if the audience could hear from Gingrich’s wife, Callista, who had been standing silently at his side. “I believe truly that he is the best person to lead our country,” she offered.